An attorney for the NRA filed documents Monday at the 11th U.S. Circuit Court of Appeals after a federal judge last week issued an injunction against a Texas law that bars people under 21 from carrying handguns outside their homes for self-defense.

While the details of the Florida and Texas laws are different, the NRA contends that they involve similar underlying issues about gun restrictions on young adults.

"The (Texas) court's opinion confirmed that young adults come within the Second Amendment's protections, and that banning young adults' right to purchase (or carry) a firearm is inconsistent with this nation's historical tradition of firearm regulation," NRA attorney John Parker Sweeney wrote in a filing known as supplemental authority.

A panel of the 11th U.S. Circuit Court of Appeals heard arguments in May about the Florida law, which the Legislature and then-Gov. Rick Scott approved after a mass shooting at Parkland's Marjory Stoneman Douglas High School that killed 17 people. The gunman, former Marjory Stoneman Douglas student Nikolas Cruz, was 19 at the time of the shooting.

The law banned sales of rifles and other types of long guns to people ages 18 to 20. Federal law already barred sales of handguns to people under 21.

The NRA challenged the Florida law, but Chief U.S. District Judge Mark Walker upheld the measure's constitutionality. That prompted the NRA to go to the Atlanta-based appeals court, where the case remains pending.

Walker, in part, focused on a landmark 2008 U.S. Supreme Court decision known as District of Columbia v. Heller. While the Heller case is broadly considered a major victory for gun-rights supporters, it also said certain "longstanding prohibitions" about guns do not violate the Second Amendment, according to Walker's ruling.

The Heller case cited prohibitions on such things as felons and mentally ill people possessing guns, Walker concluded that restrictions on 18-to-20-year-old people buying guns were "analogous" to the restrictions cited in the Heller case.

"In short, Heller's listed regulations are similar to restrictions on the purchase of firearms by 18-to-20-year-olds; all target specific groups that are thought to be especially dangerous with firearms," he wrote.

But the NRA has fought that conclusion and cited the ruling last week by U.S. District Judge Mark Pittman in the Texas case to try to bolster its arguments.

Pittman wrote that the "longstanding prohibitions regarding felons and the mentally ill were based on an individualized determination that allowing the person in question unfettered access to firearms would pose a threat to public safety. Texas's statutory scheme does the opposite. The scheme starts by prohibiting 18-to-20-year-olds from carrying a handgun for self-defense outside the home. Only if a rare exception applies may an 18-to-20-year-old seek to obtain a license to carry. And rather than determining that a person in question is a threat to public safety, certain exceptions require an individualized determination before allowing a person to exercise their Second Amendment rights."

The Fort Worth-based judge also wrote that the Second Amendment does not "mention any sort of age restriction."

"With this guidance, the court asks a simple question: Are law-abiding 18-to-20-year-olds properly considered members of the political community and a part of the national community?" Pittman wrote. "The answer is yes. And based on that answer, the court concludes that law-abiding 18-to-20-year-olds are a part of 'the people' referenced in the Second Amendment."